DataAdapter ConnectionString属性尚未初始化

    private DataSet ds = new DataSet();
    DataTable dt = new DataTable();
    private SqlDataAdapter dap = new SqlDataAdapter();
    BindingSource bs = new BindingSource();

这是我调用数据库数据的方法：
public DataSet AccessDBData(string sqlString, string tableName)
{
try
{
using (System.Data.SqlClient.SqlConnection sqlconn = new System.Data.SqlClient.SqlConnection(System.Configuration.ConfigurationManager.AppSettings["strConnection"]))
{
sqlconn.Open();
using (System.Data.SqlClient.SqlCommand odbCommand = new System.Data.SqlClient.SqlCommand())
{
odbCommand.Connection = sqlconn;
odbCommand.CommandText = sqlString;
dap.SelectCommand = odbCommand;
dap.Fill(ds, tableName);
}
sqlconn.Close();
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message + ex.StackTrace);
}
return ds;
}

            /// <summary>
    /// 绑定数据到DataGridView
    /// </summary>
    private void BindDataToDataGridView()
    {
            string selectsql = string.Format("select * from {0}", DBModels.CoalVerifiedHole.TableName);
            AccessDBData(selectsql, DBModels.CoalVerifiedHole.TableName);
        bs.DataSource = ds.Tables[0];
        dt = ds.Tables[0];
        bindingNavigator1.BindingSource = bs;
        dgv_CoalVerifiedHole.DataSource = bs;
        dgv_CoalVerifiedHole.Columns["ID"].Visible = false;
    }

            private void btnSave_Click(object sender, EventArgs e)
    {
        try
        {
            if (MessageBox.Show("确定要保存吗？", "提示！", MessageBoxButtons.OKCancel, MessageBoxIcon.Warning, MessageBoxDefaultButton.Button2) == DialogResult.OK)
            {

                if (dap != null)
                {
                    SqlCommandBuilder Sqlcb = new SqlCommandBuilder(dap);
                    dap.UpdateCommand = Sqlcb.GetUpdateCommand();
                    dap.InsertCommand = Sqlcb.GetInsertCommand();
                    dap.DeleteCommand = Sqlcb.GetDeleteCommand();
                    if (dap.Update(ds, DBModels.CoalVerifiedHole.TableName) != 0)
                    {
                        MessageBox.Show("保存成功！", "提示");
                    }
                }
            }
        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }


            但就是保存不进去！总是说 ConnectionString属性尚未初始化.弄了两天了，怎么调试都没用。求大神指教。

看你的配置文件的strConnection是否存在

既然数据能显示 说明肯定能读到配置文件的strConnection
楼主在保存的时候应该跟踪一下代码 看看此时的strConnection变成了什么